“I’m taking what she has and making it 10 times better and giving her the shape that she wants,” Calliet — who began working with Bassett ahead of production and will continue to work with her on set — tells PEOPLE.

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“While she’s filming, she’ll be with me every day,” he continues. “We film five days a week and I’m always on set, so if she needs something to happen, I’ll be there guiding her to make sure everything is going well. I’ll be her shadow — I’ll see what she ate, how much water she drank, training her when she gets off. It will be hard on her part, but she will enjoy the results.”

“I like to set up circuits. You do each movement for 30 seconds, then you take a break, get the heart rate down to get it right back up,” he says. “The reason why I like doing it so much is because it’s the fastest and the most effective way to burn fat.”

Corey Calliet

Franz Steiner

Calliet will have Bassett, 58, cycle through moves such as mountain climbers, jump squats, lunges, push-ups and high knees for 30 seconds on, 30 seconds off, and continue the cycle for up to an hour at a time.

“It’s a very hard 45 minutes to an hour because you’re going all the time, and I don’t give too many breaks unless you’re about to puke, faint or die,” he says. “You have bring the pain every day when we train. It’s the only way you’re going to get the results to look amazing on the screen.”

He wants to particularly work on toning Bassett’s lower body for the role.

“It’s the biggest muscle group, so you’re going to burn a lot of calories while doing it,” he explains. “I’m going through a lot of old-fashioned moves — lunges, squats, leg extensions, leg curls, but in the HIIT form. I’m not going to do too many hard, sculpting movements; this is more conditioning, taking what she already has — the great foundation of the body she has — and make it better.”

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In addition to her training sessions, Calliet will be working with Bassett on her diet to make sure it’s on track throughout filming.

“Her food is going to make sure that she’s nourished throughout the film,” says Calliet, who will put her on a diet plan consisting of balanced protein, fats and carbohydrates. “You don’t want to get tired, so she’ll be eating a lot of protein such as fish and grilled chicken, and carbohydrates like sweet potatoes, brown rice, jasmine rice. It’s basic dieting, nothing fancy. I just will watch her body and give her body what it needs when it needs it.”

Bassett has been a dream client for Calliet so far.

“She’s very attentive and takes the knowledge that she needs from me to be able to utilize it,” he says. “She loves fitness, she loves to work out. She wants to do it and she doesn’t quit. We were going hard and she would not stop. That’s what I like about her— at her age, she still has it in her to make her want her go more.”

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